30G

Improves the detail, which are requirements of low strength: thrust axis, cylinders, wheels, bolts, nuts, screws and others.

Classification

Country	Section	Category
Country	Section	Category
CIS, Russia, Ukraine	Structural steel	Alloyed structural steel

Chemical composition

Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	P, %	C, %	S, %
Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	P, %	C, %	S, %
GOST 4543-71	97.31–98.86	0.17–0.37	0.7–1	< 0.3	< 0.3	< 0.3	< 0.035	0.27–0.35	< 0.035

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Physical characteristics

Temperature, °C	$E\cdot 10^{9}$ , $MPa$	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$\rho$ , $\frac{kg}{m^3}$	$c\cdot 10^{-3}$ , $\frac{J}{kg\cdot K}$
Temperature, °C	$E\cdot 10^{9}$ , $MPa$	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$\rho$ , $\frac{kg}{m^3}$	$c\cdot 10^{-3}$ , $\frac{J}{kg\cdot K}$
20	204			7810
100		12.6	76		0.47
200		13.9	65		0.483
300		14.6	53		0.546
400		15	44		0.601
500		15.5	38		0.764
600		15.6
700		14.8

Mechanical properties at 20 °C

Rolling	Standard	Size, mm	Tension	Classifiers	$\sigma _{U}$ , $MPa$	$\sigma_{P}$ , $MPa$	$\epsilon_L$ , %	$\psi$ , %	$KCU\cdot 10^{3}$ , $\frac{J}{m^2}$	Treatment
Rolling	Standard	Size, mm	Tension	Classifiers	$\sigma _{U}$ , $MPa$	$\sigma_{P}$ , $MPa$	$\epsilon_L$ , %	$\psi$ , %	$KCU\cdot 10^{3}$ , $\frac{J}{m^2}$	Treatment
Rod	GOST 4543-71	25			540	315	20	45	780	Tempering 860 ° C, the water, leave 600 ° C, air

Brinell hardness number

Rolling	Standard	Classifiers	Value, HBW
Rolling	Standard	Classifiers	Value, HBW
Alloy	GOST 4543-71	annealing	197
The plates	GOST 1577-93	normalization	217
The plates	GOST 1577-93	annealing	1870

Technological Properties

Weldability	Flake Susceptibility	Propensity to temper brittleness
Weldability	Flake Susceptibility	Propensity to temper brittleness
Boundedly welded	not sensitive	inclined

Critical point temperatures

Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K	Mn, K
Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K	Mn, K
723	810	785	680	870

Analogues

USA	Germany
USA	Germany
G10330	1.1170 (28Mn6)

Standards

Standard	Description
Standard	Description
GOST 4543-71

Description of chemical elements

Element	Units of measurement	Description
Element	Units of measurement	Description
Fe	%	Iron
Si	%	Silicon
Mn	%	Manganese
Cr	%	Chrome
Cu	%	Copper
Ni	%	Nickel
P	%	Phosphorus
C	%	Carbon
S	%	Sulfur

Description of physical characteristics

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
$E\cdot 10^{9}$	$MPa$	Elastic modulus
$\alpha\cdot 10^{6}$	$K^{-1}$	Coefficient of thermal (linear) expansion (range 20°C–T)
$\varkappa$	$\frac{W}{m\cdot K}$	Coefficient of thermal conductivity (the heat capacity of the material)
$\rho$	$\frac{kg}{m^3}$	The density of the material
$c\cdot 10^{-3}$	$\frac{J}{kg\cdot K}$	The specific heat of the material (range 20°C–T)

Description of mechanical properties

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
$\sigma _{U}$	$MPa$	Ultimate tensile strength
$\sigma_{P}$	$MPa$	Proportionality limit
$\epsilon_L$	%	Elongation at break (longitudinal)
$\psi$	%	Reduction in cross section on fracture
$KCU\cdot 10^{3}$	$\frac{J}{m^2}$	Impact toughness

Designation of types of weldability

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
no limits		Welding is performed without heating and without subsequent heat treatment
Boundedly welded		Welding is possible with heating up to 100–120 °C and subsequent heat treatment
Difficult to weld		For obtaining quality welded joints, additional operations are required: heating up to 200–300 °C for welding, heat treatment after welding — annealing
Not applicable for welded structures

Description of temperatures of critical points

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
Ac₁	K
Ac₃(Ac_m)	K
Ar₃(Arc_m)	K
Ar₁	K
Mn	K